Improvement in steam-boilers



NAPETERS', PHDTOLITHOGRAPHER. WASHING-TUN. D C.

UNITED STATES PATENT OFFICE.

JAMES VIGIITMAN, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN STEAM-BOILERS.

To all whom it may concern.-

Be it known that I, JAMES WIGHTMAN, of

the city of Pittsburg, in the county of Alle-V gheny and State of Pennsylvania, have invented certain new and useful Improvements in Steam-Boilers especially adapted for Marine Steam-Engines, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings of the same, which makes part of this specification, and in which Figure'l represents a longitudinal section of a boiler having my improvements applied thereto. Fig. 2 represents a transverse section of the same at the line 1 l of Fig. l; and Fig. '3 represents a transverse section at the line 0c of Fig. l, the red lines representing the boiler on a vessel when careened to show the relative position of the flues and water-line under such circumstances.

The object of my invention is to combine the advantages of cheapness of construction and facility of cleaning and repairing which the Hue-boiler embraces with the advantage of great heating-surface exposed by a comparatively small quantity of water which the tubular boiler presents, and at the same time avoid the difficulties of cleaning and repairing, from which the tubular boiler is never free, and the necessity for carrying and heating a great weight of water for no other purpose than to ll up useless spaces between and belouT the large end fines in the flueboiler as heretofore constructed.

The object of my invention is,furthcr, to maintain. a constant distance between the top of the fines and the surface of the water, whether the vessel on which the boiler is car ried be on an even keel or careened.

The external shell of the boiler and furnace may be made of the usual form. The interior of the firebox is also of the usual form, but its arch or roof A, instead of terminating' as usual in flue or tubular boilers at a iue-sheet a-t the back of the fire-box, it extends through to the rear end of the boiler, where it terminates atv the iiuesheet B, forming the front side of the smoke-box or uptake-flue. A counter-arch, l, is connected with the arch A, leaving an included space to form a flue whose transverse section corresponds in outline to that of a short and thick elliptical spindle. This counter-arch extends from the bridge D to the rear side, L, of the uptake, and is placed a short distance above the bottom E of the cylindrical part of the boiler, and is concentric therewith, leaving a narrow Waterspace, F, between the two. This spindle-shaped iiue made in this mannergves a a very great area for its height, and permits the llame to enter it so freely, and so much of its upper arch is exposed to the direct radiation of heat from the fuel upon the grat-e, that its heating-power is much greater than that of ordinary fines, and is nearly equal in this respect to the fire e surface of the furnace. Above this direct spindle-nue a series of return-lines, G, are arranged in an arc of a circle concentric with the arch A of the fire-box and direct fiue. These fines are for the purpose of conducting the smoke and ame from the uptake H to the chimney I, and while doing so to transmit the heat from the gases and flame passing within them to the water in the boiler lying in contact with their outsides. These ues G terminate at one end in the front head, J, of the boiler, and at the other in the fine-sheet B on the front of the uptakeiiue H.

The radius of curvature in which the flues G are arranged is such that if the vessel should carcen the eXtreme position n which her deck would stand at an angle of thirty degrees to the horizon, the tubes would not even then be uncovered. This will protect the boiler effectually against the overheating of the fines in consequence of being uncovered when the vessel careens, which is be-V lieved by many to be the most fruitful cause of explosions of boilers on steamboats of the western and southern rivers.

The arch A and countersarch C maybe connected by a series of vertical tubes, K, to strengthen them against collapsing, or they may be stayed by radial bolts M, connecting them with the external shell, as represented by red lines; or both these methods of staying the arches may be employed together, as in the judgment of the constructor may be deemed most expedient.

For the purpose of collecting the sediment deposited from the water and drawing it out of the boiler more readily, a mud-leg may be connected with the rear end of the bottom of the shell, in the lower end oil which a blow-off cock may be set in the usual manner.

Vith fire box and ucs constructed and arranged in the shell described, there is a thin sheet of water surrounding the whole of the fire and flue surfaces, with a sufficient quantity above thc tlucs to supply the evaporation, so that in case the feed-pump should cease to operate for a short time there would be no danger of the water suddenly getting too low; but except that part of the body of water marked N to form a necessary supply at the upper part of the boiler there is elsewhere barely a sheet of water surroundimg,` the flue and iire surfaces of sufficient thickness to conduct away the heat, so that a vessel Fitted with this boiler would not be loaded with superfluous water, which is a matter of `great consequence in the navigation of shallow and rapid rivers where it is necessary to obtain the greatest possible power with the least possible weight of boiler.

Having thus described m yim proved steamboiler, what I claim therein as new, and ded sire to secure by Letters Patent, is-

The arrangement of the arch or' roof of the fire-box extending through to the uptake and connected with a counter-arch in such manner as to form an elliptical ilue lto form a communication between the furnace and uptake in connection with a series of small return-lines above the roof of the flre-boXrand elliptical flue, and in a curve concentric therewith, so that the upper side of the highest Hue will be at the same distance, or thereabout, below the upper surface of the water within the boiler, whether the latter be upright, as when a vessel on which it is placed is on an even keel, or inclined, as when the vessel is careened, substantially as set forth herein.

In testimony whereof l haverhereunto subscribed my name.

JAMES VlGl-ITMAN.

Witnesses:

F. VIERHELLER, ANDREW LONG. 

